bo 
or 
MARINE MOLLUSCA OF THE UNITED STATES. 
* Shell ventricose, rounded. Nos. 1, 2, 3. 
* Shell angulated by revolving ribs. Nos. 4, 5. 
1. F. Isuanpicus, Gmelin. Fig. 34. 
(Murez.) Syst. Nat., 3555. 1790. « 
Murex corneus, Pennant, Brit. Zool., iv. 124, t. 76, £99. 1777. 
Fusus corneus, Say,-Amer. Conch., t. 29. 
Shell elongated, symmetrically fusiform; spire regularly atten- 
uated to the apex; volutions eight, slightly convex ; body-whorl 
equally inflated, its surface covered with between forty and fifty 
small revolving ribs which are conspicuous through the epidermis ; 
these become almost effaced towards the outer lip, when the ver- 
tical, sinuous striz appear in their place. These ribs, or revolving 
elevated lines, are reduced to fifteen on the next whorl above, dimi- 
nishing innumbersas they ascend, theintervening furrows becoming 
more profound, with very faint traces of vertical lines. Aperture 
oblong-ovate, half the length of the shell; canal short, sinuous and 
wide. Callus on the columella broad; lip sharp, very minutely 
impressed by the terminations of the revolving lines. Color— 
Epidermis horn-colored or soiled brown; surface beneath whitish 
opalescent ; within, pearly white. 
Length of shell 2.9 inches. 
Animal white, with irregular black spots; foot rounded, rectan- 
gular; eyes black. 
Massachusetts, northward. 
2. F. premaus, Gould. Fig. 35. 
Invert. Mass., 1st edit., 284, £199. 1841. 
Shell same shape and similarly marked as Ff. Islandicus, but 
having only six whorls and only one-fourth the size, being about 
three-quarters of an inch in length. Animal pure white, with large 
foot, broadly truncate in front. 
Maine, northward. 
3. F. ventRicosus, Gray. Fig. 36. 
Zool., Beechy’s Voyage, 117. 
Fusus Islandicus (Var.), Kiener, Sp. t. 15, f. 2. 
Shell subfusiform, ventricose ; whorls five, rounded, rapidly at- 
tenuating to a blunt apex; body-whorl much inflated, composing 
the greater part of the shell. Surface covered with a velvety 
epidermis, under which numerous minute and regular revolving 
lines, with a few vertical wrinkles, are apparent. Spire short, not 
exceeding .4 above the body-whorl; lip simple, smooth; colu- 
